Located within the borders of Ardahan and Kars provinces, Lake Cildir is the largest freshwater lake and the second largest lake in the Eastern Anatolia Region with an area of 123 km2. Located at an altitude of 1959 meters above sea level, the deepest point of the lake is 42 meters. Lake Cildir is a natural barrier lake formed by a lava flow and a rubble fin. Fed by many streams and springs, the only outlet of the lake is Telek Stream, a branch of Arpacay, located in the northwest of the Armenian border. The largest is the island next to the Akcakale ruins. Very little vegetation is developed around the lake, but intensive livestock farming is practiced in the meadows surrounding the lake. Fishing, which can be done in all four seasons of the year, is an important source of economic income for the local people. Fishing in the lake is an important human activity, and fish is caught by breaking the thick layer of ice in the lake, which freezes in winter. The most important fish species (mirror) caught in the lake is Carp (Cyprinus carpio). However, during the dry seasons, the lake level declines rapidly and therefore the reed beds, which are necessary for the reproduction of species such as carp, become narrower. However, the uncontrolled fishing of many fishermen by not complying with the prohibitions negatively affects the fish stocks.
Just northwest of the lake are marshes and wet meadows separated by a bank. In general, the surrounding of the lake is pasture and its harsh climate does not allow agriculture. It is possible that the diversion tunnels built by DSI to feed the lake both carry the pollution load from other basins to the lake and cause the meadows, which are very important for livestock, to dry out. In addition, the northern deviation, the construction of which has not yet been completed, will seriously affect the grass yield of the Karaçay plain, which is a very important meadow of Cildir. It is stated that the unconscious use of agricultural chemicals (especially fertilizers with high nitrogen content) used in the agricultural areas in and around the lake, without ignoring the ecological and climatic conditions of the region, has negative effects on the lake. Uncontrolled and excessive hunting, erosion and High nutrient input It poses a threat to Lake Cildir. Although there is no excessive pollution in the lake, there is still an increasing domestic pollution. Increasing human pressure on the islands is negatively affecting the species that use these areas for hatching. The planned hotel should be reconsidered. With the increasing tourism in recent years, human pressure has increased and touristic facilities have started to be built.